This invention is generally directed to photoresponsive imaging members, and more specifically the present invention is directed to layered photoresponsive members having incorporated therein certain perylene pigment compositions as photogenerating components, and arylamine hole transport layers. Thus, in one embodiment the present invention envisions the selection of specific cis, trans naphthalene perylene pigment compositions as organic photogenerator material components in photoresponsive imaging members containing therein arylamine hole transport molecules. The aforementioned photoresponsive imaging members can be negatively charged when the perylene photogenerating layer is situated between the hole transport layer and the substrate; or positively charged when the hole transport layer is situated between the photogenerating layer and the supporting substrate. Additionally, the photoresponsive imaging members with the perylene pigment compositions as photogenerator substances, and wherein the member further includes therein an aryl amine hole transport layer, are useful in electrophotographic printing and imaging processes, especially xerographic processes wherein negatively charged or positively charged images are rendered visible with developer compositions of the appropriate charge. Of specific importance with respect to the imaging members of the present invention is their utilization in electrophotographic imaging processes wherein diode lasers are selected, since the aforementioned members have sensitivity in the wavelength region extending beyond 720 nanometers, and more specifically possess sensitivity in the range of from about 750 to about 780 nanometers.
Layered photoresponsive imaging members are generally known, reference for example U.S. Pat. No. 4,265,900, the disclosure of which is totally incorporated herein be reference, wherein there is described an imaging member comprised of a photogenerating layer, and an aryl amine hole transport layer. Examples of substances selected for the photogenerating layer of this patent include trigonal selenium, metal phthalocyanines, and metal free phthalocyanines. Additionally, there is described in U.S. Pat. No. 3,121,006, the disclosure of which is totally incorporated herein be reference, a composite xerographic photoconductive member comprised of finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. The binder materials disclosed in the U.S. Pat. No. 3,121,006 comprise a material which is incapable of transporting for any significant distance injected charge carriers generated by the photoconductive particles. Accordingly, as a result, the photoconductive particles must be in a substantially contiguous particle-to-particle contact throughout the layer for the purpose of permitting charge dissipation required for a cyclic operation. with a uniform dispersion of photoconductive particles,, a relatively high volume concentration of photoconductor material, about 50 percent by volume, is usually necessary to obtain sufficient photoconductor particle-to-particle contact for rapid discharge. This high photoconductive loading can result in destroying the physical continuity of the resinous binder, thus significantly reducing the mechanical properties thereof. Illustrative examples of specific binder materials disclosed in the U.S. Pat. No. 3,121,006 include polycarbonate resins, polyester resins, polyamide resins, and the like.
Many other patents are in existence describing layered photoresponsive imaging members containing photogenerating substances, such as U.S. Pat. No. 3,041,167, which discloses an overcoated imaging member with a conductive substrate, a photoconductive layer, and an overcoating layer of an electrically insulating polymeric material. This member is utilized in an electrophotographic copying process by, for example, initially charging the member with an electrostatic charge of a first polarity, and imagewise exposing to form an electrostatic latent image which can be subsequently developed to form a visible image. Prior to each succeeding imaging cycle, the imaging member can be charged with an electrostatic charge of a second polarity, which is opposite in polarity to the first polarity. Sufficient additional charges of the second polarity are applied to create across the member a net electrical field of the second polarity. Simultaneously, mobile charges of the first polarity are created in the photoconductive layer such as by applying an electrical potential to the conductive substrate. The imaging potential, which is developed to form the visible image, is present across the photoconductive layer and the overcoating layer.
Photoresponsive imaging members with squaraine photogenerating pigments are also known, reference U.S. Pat. No. 4,415,639, the disclosure of which is totally incorporated herein by reference. In this patent there is illustrated an improved photoresponsive imaging member with a substrate, a hole blocking layer, an optional adhesive interface layer, an organic photogenerating layer, a photoconductive composition capable of enhancing or reducing the intrinsic properties of the photogenerating layer, and an arylamine hole transport layer. As photoconductive compositions for the aforementioned member, there can be selected various squaraine pigments, including hydroxy squaraine compositions. Moreover, there is disclosed in U.S. Pat. No. 3,824,099 certain photosensitive hydroxy squaraine compositions. According to the disclosure of this patent, the squaraine compositions are photosensitive in normal electrostatographic imaging processes.
Photoconductive imaging members containing perylene pigments are also known. There is thus described in Hoechst European Patent Publication No. 0040402, DE3019326, with a filing date of May 21, 1980, N,N'-disubstituted perylene-3,4,9,10-tetracarboxyldiimide pigments as photoconductive substances. Specifically, there is disclosed in this publication evaporated N,N'-bis(3-methoxypropyl)perylene-3,4,9,10-tetracarboxyldiimide dual layered negatively charged photoreceptors with improved spectral response in the wavelength region of 400 to 700 nanometers. A similar disclosure is revealed in Ernst Gunther Schlosser, Journal of Applied Photographic Engineering, Vol. 4, No. 3, page 118 (1978). There is also disclosed in U.S. Pat. No. 3,871,882 photoconductive substances comprised of specific perylene-3,4,9,10-tetracarboxylic acid derivative dyestuffs. In accordance with the teachings of this patent, the photoconductive layer is preferably formed by vapor depositing the dyestuff in a vacuum. Also, there is disclosed in this patent dual layer photoreceptors with perylene-3,4,9,10-tetracarboxylic acid diimide derivatives, which have spectral response in the wavelength region of from 400 to 600 nanometers.
Moreover, there are disclosed in U.S. Pat. No. 4,419,427, electrographic recording mediums with a photosemiconductive double layer comprised of a first layer containing charge carrier perylene diimide producing dyes, and a second layer with one or more compounds which are charge transporting materials when exposed to light, reference the disclosure in column 2, beginning at line 20. Also of interest with respect to this patent is the background information included in columns 1 and 2, wherein perylene dyes of the formula illustrated are presented.
Furthermore, there is presented in copending application U.S. Ser. No. 587,483, entitled Photoconductive Devices Containing Perylene Dye Compositions, the disclosure of which is totally incorporated herein by reference, an ambipolar imaging member comprised of a supporting substrate; a photoconductive layer comprised of specific perylene dyes different than the perylene pigments of the present invention, which dyes are dispersed in a polymeric resinous binder composition; and as a top layer a specific aryl amine hole transporting substance dispersed in an inactive resinous binder. Examples of perylene dyes selected for the photoconductive layer of the copending application include N,N'-di(2,4,6-trimethylphenyl)perylene 3,4,9,10-tetracarboxyldiimide, N,N'-di(2,4,6-trimethoxyphenyl)perylene 3,4,9,10-tetracarboxyldiimide, and N,N'-di(2,6-dimethylphenyl) perylene 3,4,9,10-tetracarboxyldiimide. Additionally, there is disclosed in U.S. Pat. No. 4,429,029 electrophotographic recording members with perylene charge carrier producing dyes, and a charge carrier transporting layer.
In addition, there is illustrated in U.S. Pat. No. 4,587,189, the disclosure of which is totally incorporated herein by reference, photoconductive imaging members with perylene components inclusive of benzimidazole perylenes, which are similar to those of the present invention with the primary exception that they do not contain therein a naphthalene ring structure attached to the nitrogen atoms as more fully illustrated hereinafter. Although the imaging members of the aforementioned patent are useful for their intended purposes, there continues to be a need for highly thermally stable perylenes with spectral response extending into the near infrared. Furthermore, there continues to be a need for perylenes which can be vacuum evaporated to form a contiguous layer which is impervious to organic solvents, such as methylene chloride and the like.
Additionally, there are disclosed in U.S. Pat. No. 4,556,622, photoconductive layers with a halogenated perylene dye sensitizer, reference for example Formulas IV, and IVa, columns 3, and 4. The aforementioned perylenes, for example, do not contain a naphthalene ring structure attached to the nitrogen atom as is the situation with the photogenerating pigments of the present invention; and moreover, this patent does not teach the selection of specific types of arylamines as hole transporting substances thereby enabling rapid transport of charge in the imaging member permitting images of acceptable resolution to be formed for a substantial number of imaging cycles. This patent is of further interest with respect to, for example, the perylene tetracarboxylic acid pigments of Formula III wherein B is a fused on aromatic system, reference German Laid Open Application No. DOS 2314051, see column 2, lines 5 to 12. Accordingly, the aforementioned perylenes are similar to those of the present invention, particularly when B is a phenyl grouping. In U.S. Pat. No. 4,156,757, there are disclosed electrical conductive and semiconductive devices contacting perylene derivatives, of the formulas illustrated in column 1, lines 45 to 52. This reference, however, does not disclose naphthalene perylenes, nor mixtures of certain cis and trans isomers thereof as illustrated herein.
While the above-described photoresponsive imaging members are suitable for their intended purposes, there continues to be a need for improved members, particularly layered members, having incorporated therein specific perylene pigment compositions and aryl amine hole transport compounds. Additionally, there continues to be a need for layered imaging members comprised of specific aryl amine charge transport compositions, and as photogenerating materials naphthalene cis, trans perylene pigments, which members possess sensitivity in a wavelength region exceeding 720 nanometers, have low dark decay characteristics, and high charge acceptance values. Further, these members can be selected for a number of imaging cycles in a xerographic imaging or printing apparatus. Furthermore, there continues to be a need for photoresponsive imaging members which can be positively or negatively charged thus permitting the development of images, including color images, with positively or negatively charged toner compositions. Moreover, there continues to be an important need for disposable imaging members with nontoxic organic pigments. Also, there is a need for disposable imaging members useful in xerographic imaging processes, and xerographic printing systems wherein, for example, light emitting diodes (LED), helium cadmium, or helium neon lasers are selected; and wherein these members are particularly sensitive to the infrared region of the spectrum, that is, from about 720 to about 800 nanometers.